As every good detective knows, it is the details that give the game away. The French rugby bible Midi Olympique, its yellow pages as distinctive as FT pink, has decided to publish two issues a week for the first time in its history. L'Equipe, not to be outdone, is launching a new weekly rugby magazine next month. In the suburbs of Manchester, Sale's director of rugby Philippe Saint-André is finding it increasingly hard to prise his two French forwards Sébastien Bruno and Sébastien Chabal off the training field. "After almost every session," shrugs Saint-André, "they insist on doing extra work." So much for the laissez-faire lifestyles with which French rugby men used to be synonymous.

Anyone who views all this as coincidence is forgetting which country is staging the 2007 Rugby World Cup. French rugby will be the centre of attention in September and October next year and is determined to look suitably chic. The national coach Bernard Laporte, at a conservative estimate, now has 50 players who could slot into most teams in the world. As the sweating Sharks expats Bruno and Chabal clearly understand, there is no automatic passport into the eventual tournament squad of 30.

All of which is deeply ominous for England, France's fiercest rugby-playing neighbour and the only European country with the resources to match Les Bleus. It also adds a tantalising extra dimension to this year's RBS Six Nations Championship. What if France, after years of being the crumbliest, flakiest type of chocolat, are finally on the brink of being consistent hard nuts? What if they start to make opponents look second rate up front and behind the scrum every week, switching between power and pace at will? What if the Gallic domination of the Heineken Cup, which French sides are threatening to win for a third time in four seasons, were to be extended to the Six Nations?

For England this tournament has, therefore, become as psychologically crucial as any since Sir Clive Woodward's side banished their grand slam bogey in the build-up to the 2003 World Cup. There is no question the French, in terms of developing a trophy-winning squad for 2007, are currently further ahead than Andy Robinson's England. In almost every position they not only have options but proven stand-ins of a similar class to those the All Blacks unearthed on their all-conquering European tour in the autumn.

Consider, for a moment, the French back-row conundrum. They will kick off the tournament in Edinburgh with Yannick Nyanga, Rémy Martin and Julien Bonnaire. They could equally well have Thomas Lièvremont or Chabal or Imanol Harinordoquy or Serge Betsen. The redoubtable Olivier Magne is still playing at London Irish; to those who watch Toulouse in full flow it seems remarkable that Grégory Lamboley and Jean Bouilhou do not get much of a look-in.

The same embarrassment of riches is evident behind the scrum, with the possible exception of fly-half. On the other hand their two best goal-kickers are the scrum-halves Dimitri Yachvili and Jean-Baptiste Elissalde so they can afford to indulge themselves with a gifted if erratic playmaker such as Frédéric Michalak. As a leather-jacketed Serge Blanco sat sipping mineral water watching his beloved Biarritz crush Saracens the other week, the thought occurred that French rugby has never been in better shape.

So what can Robinson's England do to catch up? Even if France inexplicably revert to languid type and somehow lose at Murrayfield this weekend, the game likely to shape the 2006 Six Nations is the Anglo-French encounter in Paris on Sunday March 12. To win, England will have to prove the French forwards are over-rated and emasculate their strutting backs on their home track. Simple, non?

As England's recalled former captain Lawrence Dallaglio admitted this week, there is no time to waste. If Robinson and co want to regain lost ground they simply have to push on over the next six weeks. "This tournament is the foundation for the next 18 months. The time leading up to the World Cup is diminishing with every day so this tournament is important for every team, not just England," insisted Dallaglio sternly. "A World Cup is not just about turning up and winning. You have to put together results on the way. Every country will want to start doing that in this championship and our game against France in Paris will be a great benchmark."

England's defence coach Phil Larder was even blunter on Wednesday, going as far as to query the core skill levels of his elite players and acknowledging England "need a couple of gamebreakers" if they are to develop the tactical flexibility required by all truly great teams. Into that category, clearly, fall the likes of James Simpson-Daniel, Tom Voyce and Mathew Tait, none of whom have been trusted to start against Wales as a consequence of the limited preparation time the squad have enjoyed together.

The snag, as the flanker Joe Worsley reminds us, is that England's main rivals have been conducting similar calculated experiments for the past two years. France's strength in depth, he reckons, is now scary. "They have more players with more international experience, which makes a difference particularly if you get injuries. It means they have more strings to their bow which, at the end of the day, is vital. No side is unbeatable but to me they will be one of the major threats at the next World Cup. It's in their own country and the number of players they can choose from is phenomenal. In terms of pure skill and athletic ability they worry me more than the Kiwis."

Worsley's antidote is beautifully simple. "How are we going to get ahead of them? By doing what we've always done over the years, namely working harder than them. Our scrums, defence and kicking game should always be quite good. We've just got to work on developing other facets of our game, working together as a team and reading situations better. But all of that takes time."

And so, with all due respect to Wales, Ireland, Scotland and Italy, it is England's game at the Stade de France which senior players are regarding as the acid test. Worsley cites England's gritty 15-9 win in Paris in 2000 as something to aspire to. "That win gave us a lot of confidence. We ballsed up the grand slam that year, despite playing some great rugby, but winning in Paris gave us a lot of confidence. It was one of the big stepping stones in terms of getting to the World Cup."

It will be a tall order. The Welsh will read this and wonder if, yet again, they can sneak up on England's blind side. Ireland, with their sublime backs, will be keen to test whether the foundations England felt they laid in the autumn are as firm as they imagine. France's coach Laporte, meanwhile, spoke for every English fan last week as he rocked back in his chair at the Hurlingham Club in London and pondered familiar questions. "Wilkinson? Vickery? Why, after winning the World Cup, have so many players finished or been injured? Why?" Unearthing more English likely lads is not just desirable but an increasing matter of urgency.